Aloe Emodin‐Induced Apoptosis in t‐HSC/Cl‐6 Cells Involves a Mitochondria‐Mediated Pathway

Abstract

The aim of our study was to clarify the apoptosis pathway induced by aloe emodin, an hydroxyanthraquinone present in aloe vera leaves, in rat hepatic stellate cells transformed by simian virus 40 (t-HSC/Cl-6), which retain the features of activated rat stellate cells. Apoptosis was determined by DNA fragmentation, caspase activity assay and western blotting analysis. Treatment of t-HSC/Cl-6 cells with 12.5, 25, or 50 mM aloe emodin inhibited t-HSC/Cl-6 cell viability in a dose-and time-dependent manner. The induction of apoptosis by aloe emodin was confirmed by typical DNA ladder formation and annexin v-propidium iodide flow-cytometric analysis. Aloe emodin treatment of t-HSC/Cl-6 cells caused activation of caspase-3 and caspase-9, detected with a caspase activity assay, although no change was observed in caspase-8 activity. Western blotting showed caspase-3 and caspase-9 active forms and the subsequent proteolytic cleavage of poly(ADP-ribose) polymerase. Aloe emodin induced mitochondrial membrane depolarization. Our data also show that cytochrome c increased in the cytosol but decreased in the mitochondria in a time-dependent manner. Increased Bax and unchanged Bcl-2 levels resulted in an increased Bax/Bcl-2 ratio. Thus, our research provides evidence that aloe emodininduced apoptosis involves a mitochondria-associated apoptosis pathway.

Apoptosis by aloe‐emodin is mediated through down‐regulation of calpain‐2 and ubiquitin‐protein ligase E3A in human hepatoma Huh‐7 cells

“…AE has been shown to induce DNA damage through generation of ROS in human lung carcinoma cells (Lee et al, 2006). Studies have also suggested that AE could induce apoptosis via interruption of cell proliferation (Lian et al, 2005).…”

Preparation of 1,8-Di-O-alkylaloe-emodins and 15-Amino-, 15-Thiocyano-, and 15-Selenocyanochrysophanol Derivatives from Aloe-Emodin and Studying Their Cytotoxic Effects

“…The extracts were successively washed with 10% NaHCO 3 , and water, and then dried over absolute MgSO 4 and filtered. The filtrate was evaporated to give a residue that was subjected to preparative TLC (5% MeOH in CH 2 Cl 2 ) to obtain compound 10 (46.9 mg, 48.3% yield, mp 97-99°C after recrystallization form acetone Table 4.…”

“…The extracts were successively washed with 5% HCl, 10% NaHCO 3 , brine and water, and then dried over absolute MgSO 4 and filtered. The filtrate was evaporated to give a residue that was subjected to column chromatography (a gradient of 0-1% acetone in toluene) to obtain compound 16 (316 mg, 53.3%).…”

“…In our preliminary investigation, these compounds also showed no marked cytotoxicity in less than 500 mM of the IC 50 valuethe concentration at which 50% of the cells are inhibited from growing. However, from the both above-mentioned reports, it is evident that a compound that possessed an alkyl chain with an appropriate length or that introduced appropriate substituents such as amino, thiocyano, and selecocyano groups in the molecule seemed to exhibit potent cytotoxic activity.In the present study, we investigate the preparation of 1,8-di-O-alkylaloe-emodins and 15-amino-, 15-thiocyano-, and 15-selenocyanochrysophanol derivatives from aloe-emodin (3) which has been known to have several pharmacological activities such as cytotoxic activity, [3][4][5] antifungal activity, 6) antibacterial activity, 7) and so on, and further we evaluate the cytotoxic effects of the synthetic derivatives on HCT 116 and Hep G2 cancer cell lines. …”

“…In the present study, we investigate the preparation of 1,8-di-O-alkylaloe-emodins and 15-amino-, 15-thiocyano-, and 15-selenocyanochrysophanol derivatives from aloe-emodin (3) which has been known to have several pharmacological activities such as cytotoxic activity, [3][4][5] antifungal activity, 6) antibacterial activity, 7) and so on, and further we evaluate the cytotoxic effects of the synthetic derivatives on HCT 116 and Hep G2 cancer cell lines.…”